Ultrasonic anemometer

Abstract

To provide an ultrasonic anemometer capable of suppressing the influence of acoustic noise on a measurement result.SOLUTION: An ultrasonic anemometer 100 includes an upper body 10 on which an ultrasonic transceiver 30 is mounted and in which a cavity 50 is formed at a position other than a portion where the ultrasonic transceiver 30 is disposed, a lower body 20 disposed away from the upper body 10 by a predetermined distance in a first direction, and a shield 60 covering an opening of the cavity 50.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to ultrasonic anemometers. [Background technology]

[0002] For example, a wind direction and speed measuring device is known that measures the wind direction and speed of a fluid to be measured based on the propagation time of ultrasonic waves transmitted and received between a pair of ultrasonic transmitters and receivers (see, for example, Patent Document 1). This wind direction and speed measuring device includes a housing in which a flow path through which the fluid to be measured flows is formed, and a pair of ultrasonic transmitters and receivers that are installed at a predetermined inclination relative to the flow path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-77643 Summary of the Invention [Problem to be solved by the invention]

[0004] There is room for improvement in the prior art in terms of acoustic noise countermeasures.

[0005] The present disclosure provides an ultrasonic anemometer that can suppress the influence of acoustic noise on measurement results. [Means for solving the problem]

[0006] The ultrasonic anemometer according to the present disclosure comprises an upper body on which an ultrasonic transmitter / receiver is mounted and in which a hollow portion is formed at a position other than where the ultrasonic transmitter / receiver is located, a lower body arranged a predetermined distance from the upper body in a first direction, and a shielding portion that covers the opening of the hollow portion. [Effects of the Invention]

[0007] The present disclosure can provide an ultrasonic anemometer that can suppress the influence of acoustic noise on measurement results. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic perspective view illustrating an ultrasonic anemometer according to an embodiment; [Figure 2] FIG. 1 is a schematic cross-sectional view illustrating an ultrasonic anemometer according to an embodiment, showing a cross section along an XZ plane. [Figure 3] 3 is a bottom view illustrating the bottom surface of the upper body and the bottom surface of the shielding plate of the ultrasonic anemometer according to the embodiment. FIG. [Figure 4] 3 is a partially enlarged cross-sectional view illustrating an umbrella portion, a cavity portion, and a shielding plate of the ultrasonic anemometer according to the embodiment. FIG. [Figure 5] 10 is a partially enlarged cross-sectional view illustrating an umbrella portion, a cavity portion, and a shielding plate of an ultrasonic anemometer according to a first modification. FIG. [Figure 6] 10 is a partially enlarged cross-sectional view illustrating an umbrella portion, a cavity portion, and a shielding plate of an ultrasonic anemometer according to a second modification. FIG. [Figure 7] 10 is a partially enlarged cross-sectional view illustrating an umbrella portion, a cavity portion, and a shielding plate of an ultrasonic anemometer according to a third modification. FIG. [Figure 8] 10 is a partially enlarged cross-sectional view illustrating an umbrella portion, a cavity portion, and a shielding plate of an ultrasonic anemometer according to a fourth modification. FIG. [Figure 9] FIG. 10 is a schematic cross-sectional view illustrating an ultrasonic anemometer according to a comparative example, showing a cross section along the XZ plane. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an ultrasonic anemometer according to an embodiment will be described with reference to the accompanying drawings. In this specification and the drawings, substantially identical components may be designated by the same reference numerals to avoid redundant description. Furthermore, in this specification, the terms "upper" and "lower" may be used. These refer to the "upper" and "lower" states shown in, for example, Figures 1 and 2, where the side where the upper body 10 is located in the Z-axis direction is referred to as "upper" and the side where the lower body 20 is located as "lower."

[0010] [Ultrasonic anemometer 100 according to the embodiment] FIG. 1 is a schematic perspective view illustrating an ultrasonic anemometer 100 according to an embodiment. FIG. 2 is a schematic cross-sectional view illustrating the ultrasonic anemometer 100 according to an embodiment, showing a cross section along the XZ plane. FIG. 3 is a bottom view illustrating the bottom surface of the upper body 10 and the bottom surface of the shielding plate 60 of the ultrasonic anemometer 100 according to an embodiment. FIG. 4 is a partially enlarged cross-sectional view illustrating the umbrella portion 40, the cavity portion 50, and the shielding plate 60 of the ultrasonic anemometer 100 according to an embodiment. Note that in each drawing, the X-axis direction, the Y-axis direction, and the Z-axis direction may be perpendicular to each other. The X-axis direction, the Y-axis direction, and the Z-axis direction do not have to be perpendicular to each other. The X-axis direction, the Y-axis direction, and the Z-axis direction may be any direction. The Z-axis direction is an example of a first direction. The X-axis direction is an example of a second direction intersecting the first direction. The Y-axis direction is an example of a third direction intersecting the first direction and the second direction. The X-axis direction and the Y-axis direction may be reversed.

[0011] The ultrasonic anemometer 100 shown in Figures 1 to 4 is a wind direction and speed measurement device that measures the wind direction and speed of a fluid to be measured based on the propagation time of ultrasonic waves transmitted and received between an ultrasonic transmitter and an ultrasonic receiver. The ultrasonic anemometer 100 can determine the wind speed from fluctuations in the speed of sound in the air (approximately 340 m / s). The distance between the ultrasonic transmitter and the ultrasonic receiver is known, and the wind direction and speed of the fluid can be measured based on the difference in the propagation time of the ultrasonic waves.

[0012] As shown in FIGS. 1 and 2, the ultrasonic anemometer 100 includes an upper body 10, a lower body 20, and multiple support columns 13. The upper body 10 and the lower body 20 are spaced apart in the Z-axis direction. The multiple support columns 13 extend in the Z-axis direction and support the upper body 10 relative to the lower body 20. The lower ends of the support columns 13 are fixed to the lower body 20, and the upper ends of the support columns 13 are fixed to the upper body 10. The upper body 10 is equipped with multiple ultrasonic transmitters / receivers 30 and a circuit board. As shown in FIG. 3, four ultrasonic transmitters / receivers 30 are arranged on the upper body 10. The ultrasonic transmitters / receivers 30 are arranged at the vertices of a substantially square.

[0013] As shown in FIG. 2, the ultrasonic anemometer 100 includes a top plate 11, a plurality of (for example, four) ultrasonic transmitters and receivers 30, and a reflector plate 21.

[0014] [Upper frame 10] The upper body 10 has a main body 15 and an umbrella portion 40. The main body 15 includes a top plate 11. The main body 15 is equipped with multiple ultrasonic transmitters and receivers 30. The top plate 11 is disposed at the bottom of the main body 15. The top plate 11 is, for example, disk-shaped. The multiple ultrasonic transmitters and receivers 30 are held to the main body 15 by holders 19. Here, the main body 15 includes a portion where the ultrasonic transmitters and receivers 30 are disposed. A housing portion may be formed inside the main body 15 to house a wiring board or the like connected to the ultrasonic transmitters and receivers 30. The portion of the upper body 10 inside the straight line L15 is the main body 15. The straight line L15 is a line extending in the Z-axis direction from the side surface 15a of the main body 15 exposed by the hollow portion 50. It can also be said that the line L15 is a line extending in the Z-axis direction from the portion where the shielding plate 60 and the side surface 15a meet.

[0015] The upper body 10 holds the ultrasonic transceiver 30 so that the bottom surface 30b of the ultrasonic transceiver 30 is exposed. The ultrasonic transceiver 30 is held by the top plate 11, with the bottom surface 30b exposed downward. The umbrella portion 40 will be described later.

[0016] [1st plane 12] The top plate 11 has a first plane 12. The first plane 12 is a surface along the X-axis direction and the Y-axis direction. The first plane 12 is the bottom surface of the top plate 11.

[0017] [Multiple ultrasonic transmitters / receivers 30] As shown in Fig. 3, the multiple ultrasonic transmitters / receivers 30 include ultrasonic transmitters / receivers 31 to 34. The ultrasonic anemometer 100 may include three or more ultrasonic transmitters / receivers 30. The ultrasonic transmitters / receivers 30 are ultrasonic transmitters that transmit ultrasonic waves and ultrasonic receivers that receive ultrasonic waves. The ultrasonic transmitters / receivers 31 and 32 are positioned apart in the X-axis direction. The ultrasonic transmitters / receivers 33 and 34 are positioned apart in the Y-axis direction.

[0018] [Lower body 20] 2, the lower body 20 has a reflector 21. The lower body 20 is disposed at a predetermined distance from the upper body 10 in the Z-axis direction. A flow path 101 is formed between the upper body 10 and the lower body 20.

[0019] [Reflector 21] The reflecting plate 21 is provided on the upper part of the lower body 20. The reflecting plate 21 is disposed so as to face the top plate 11 in the Z-axis direction. A flow path 101 is formed between the top plate 11 and the reflecting plate 21, through which the fluid to be measured can pass. The fluid to be measured may be, for example, air. The reflecting plate 21 has a surface that reflects ultrasonic waves transmitted from the ultrasonic transceiver 30. The ultrasonic waves are emitted into the flow path 101 from the bottom surface 10b of the ultrasonic transceiver 30.

[0020] [2nd plane 22] The reflector 21 has a second plane 22. The second plane 22 may be the upper surface of the reflector 21. The second plane 22 is a plane that faces the first plane 12 in the Z-axis direction and is parallel to the second plane 22. The second plane 22 is a plane that extends along the X-axis direction and the Y-axis direction. The second plane 22 is disposed in the center of the reflector 21 when viewed in the Z-axis direction. The reflector 21 has, for example, a circular shape. Furthermore, when viewed in the Z-axis direction, the second plane 22 includes an area that overlaps with the first plane 12. The second plane 22 may be formed in the center of the reflector 21, or may be formed on the entire surface of the reflector 21.

[0021] [Side 3 23] The reflector 21 has a third surface 23. The third surface 23 is formed around the second plane 22 when viewed in the Z-axis direction. The third surface 23 is formed so as to surround the second plane 22. The third surface 23 may be, for example, a conical slope. As shown in FIG. 2 , in a cross section along the XZ plane, the third surface 23 includes an inclined surface that is inclined with respect to the second plane 22. The upper end of the third surface 23 is located closer to the second plane 22 in the X-axis direction than the lower end of the third surface 23. In the Z-axis direction, the lower end of the third surface 23 is located further outward than the upper end of the third surface 23. The third surface 23 is inclined outward so as to face the opposite side to the second plane 22. The outer end of the third surface 23 is located lower than the inner end. "Outward" may also mean that the outer end is located lower than the inner end. "Downward" refers to a direction away from the top plate 11 in the Z-axis direction. The third surface 23 includes a position overlapping with the ultrasonic transceivers 30 when viewed in the Z-axis direction. The third surface 23 includes a surface disposed directly below the plurality of ultrasonic transceivers 30. The reflecting plate 21 may have only the second plane 22 and may not have the third surface 23.

[0022] [Reflected wave] Ultrasonic waves transmitted from the ultrasonic transceiver 31 on the transmitting side are reflected by the second plane 22 and received by the ultrasonic transceiver 32 on the receiving side.

[0023] [Umbrella section 40] As shown in Figures 2 to 4, the umbrella portion 40 is formed to surround the main body 15. The umbrella portion 40 is formed along the outer periphery of the main body 15. The umbrella portion 40 is an example of an inclined portion. The umbrella portion 40 has an annular shape when viewed in the Z-axis direction. The outer surface of the umbrella portion 40 forms an inclined surface 41. The portion of the upper body 10 that is outside the straight line L15 may be the umbrella portion 40.

[0024] As shown in FIG. 4, the lower part of the umbrella part 40 is formed to expand in the X-axis direction. Furthermore, as shown in FIG. 1, when the ultrasonic anemometer 100 is viewed as a whole, the lower part of the umbrella part 40 is formed to expand in the radial direction of the upper body 10. The radial direction of the upper body 10 is a direction intersecting the center line CL1 of the upper body 10 and includes the X-axis direction and the Y-axis direction. The radial direction may also be the radial direction of a virtual circle centered on the center line CL1 of the upper body 10. The inclined surface 41 is inclined so that the lower side of the inclined surface 41 is positioned outward in the radial direction of the upper body 10 compared to the upper side of the inclined surface 41. The lower side of the inclined surface 41 is positioned outward in the radial direction of the upper body 10 compared to the upper side of the inclined surface 41.

[0025] The maximum outer diameter of the umbrella portion 40 is larger than the outer diameter of the reflector 21. In the X-axis direction, the tip 40a of the umbrella portion 40 is disposed radially outward from the end 20a of the upper surface of the reflector 21.

[0026] The umbrella portion 40 includes a plate-shaped portion. The thickness direction of the plate-shaped portion of the umbrella portion 40 is a direction inclined with respect to the X-axis direction and the Z-axis direction on the XZ plane shown in FIG.

[0027] [Cavity 50] As shown in Figures 2 and 4, a hollow portion 50 is formed in the upper body 10. The hollow portion 50 is formed between the main body 15 and the umbrella portion 40 in the radial direction of the upper body 10. The hollow portion 50 is formed inside the umbrella portion 40 in the radial direction of the upper body 10. The hollow portion 50 is a recessed portion that is recessed upward. The hollow portion 50 is formed around the entire circumference of the umbrella portion 40. The hollow portion 50 is formed between the side surface 15a of the main body 15 and the inner surface 43 of the umbrella portion 40. The "inside" refers to the side closer to the center line CL1 of the upper body 10 shown in Figures 1 and 2. The "outside" refers to the side farther from the center line CL1 of the upper body 10.

[0028] [Corner portion 16a at the bottom of main body 15 of upper body 10] As shown in FIG. 4, the bottom of the upper body 10 has a corner 16a that is located more inward than the umbrella portion 40 in the X-axis direction. The bottom of the upper body 10 includes the first flat surface 12 of the top plate 11. The corner 16a may be an end of the first flat surface 12. The corner 16a may be a lower end of the side surface 15a of the main body 15. The corner 16a includes a surface that contacts the hollow portion 50. The corner 16a may also include a surface that contacts the flow path 101. In a cross section along the Z-axis direction, the corner 16a is rounded. The corner 16a includes a curved surface. The corner 16a is formed around the entire periphery of the main body 15.

[0029] [Recess 17] As shown in FIG. 4 , a recess 17 is formed in the bottom of the main body 15. The recess 17 is a groove recessed above the first plane 12. The recess 17 is formed in an annular shape when viewed in the Z-axis direction. The recess 17 is located inside the corner 16a. The recess 17 is located outside the ultrasonic transceivers 30. The recess 17 is located so as to surround the ultrasonic transceivers 30. In other words, the ultrasonic transceivers 30 are located inside the annular recess 17. In the radial direction, a convex portion 18 is formed between the ultrasonic transceiver 30 and the recess 17, protruding toward the flow path 101 more than the bottom surface 30b of the ultrasonic transceiver 30. The recess 17 may be formed at a position higher than the bottom surface 30b of the ultrasonic transceiver 30 in the Z-axis direction, or may be formed at the same height as the bottom surface 30b.

[0030] [Inclination angle θ1 of inclined surface 41 of umbrella portion 40] The umbrella portion 40 has an inclined surface 41 that is inclined at an inclination angle θ1 with respect to the first plane (XY plane, horizontal plane) 12. The inclined surface 41 is the outer surface of the umbrella portion 40. The inclined surface 41 and the inner surface 43 face each other in the thickness direction of the umbrella portion 40. The inclination angle θ1 of the inclined surface 41 of the umbrella portion 40 is set so that the kinetic energy of the raindrops 110 falling on the inclined surface 41 is greater than the surface tension energy of the raindrops 110 adhering to the inclined surface 41. The inclination angle θ1 may be, for example, 65 degrees. The inclination angle θ1 is the angle between a line along the X-axis and a line along the inclined surface 41.

[0031] [First and second parts of upper body 10] The upper body 10 may have a first portion and a second portion. The first portion is, for example, the main body 15. The second portion is the umbrella portion 40. The main body 15 and the umbrella portion 40 are formed, for example, as a single unit. The main body 15 is formed, for example, in a cylindrical shape. The umbrella portion 40 forms, for example, a conical surface. The umbrella portion 40 is connected to the main body 15 as shown in FIG. 4. The main body 15 and the umbrella portion 40 may be made of a material such as resin. The material of the main body 15 and the umbrella portion 40 is not limited to resin and may be other materials.

[0032] The umbrella portion 40 may include a protruding piece 44 that protrudes radially from the side surface 15a of the main body 15, and an inclined portion 45 that extends diagonally downward from the protruding piece 44. The protruding piece 44 connects the main body 15 and the inclined portion 45. The thickness direction of the protruding piece 44 is along the Z-axis direction. The inclined portion 45 extends diagonally downward from the radially outer end of the protruding piece 44. The outer surface of the inclined portion 45 forms an inclined surface 41.

[0033] The umbrella portion 40, which is the second portion, may be formed integrally with the main body 15, which is the first portion, or may be formed as a separate member. The umbrella portion 40 may be configured to be detachable from the main body 15. The umbrella portion 40 may have a structure that allows it to be attached to and detached from the main body 15. The umbrella portion 40 may be attached to the main body 15 via another member, for example.

[0034] [Taper of bottom 42 of umbrella portion 40] The bottom 42 of the umbrella portion 40 is tapered. The bottom 42 may be the bottom surface of the inclined portion 45. In the bottom 42 of the umbrella portion 40, the radially inner end 42a is positioned higher than the radially outer end (tip 40a). The end 42a may be the end where the bottom 42 and the inner surface 43 intersect. The angle θ2 of the taper of the bottom 42 from the first plane 12 to the Z-axis direction may be, for example, 12.5 degrees. The bottom 42 of the umbrella portion 40 is tapered, and the end 42a is positioned higher than the tip 40a. This prevents raindrops 110 that adhere to and fall on the inclined surface 41 from entering the cavity 50 in the ultrasonic anemometer 100. The raindrops 110 are prevented from moving upward along the tapered bottom 42, and thus are prevented from entering the cavity 50.

[0035] [Shielding plate 60] As shown in FIGS. 2 to 4, the ultrasonic anemometer 100 includes a shielding plate 60. The shielding plate 60 is an example of a shielding portion. As shown in FIG. 4, the shielding plate 60 is arranged to cover the opening of the cavity 50. The opening of the cavity 50 faces downward. As described above, the cavity 50 is formed to be recessed upward. As shown in FIG. 3, the shielding plate 60 is arranged outward of the multiple ultrasonic transmitters and receivers 30 in the X-axis direction and the Y-axis direction. The shielding plate 60 is formed to be ring-shaped when viewed in the Z-axis direction. The shielding plate 60 may be formed to cover the entire periphery of the opening of the cavity 50. The shielding plate 60 may be formed to cover the entire surface of the opening of the cavity 50.

[0036] 2 and 4, the shielding plate 60 has an upper surface 60a and a lower surface 60b that face each other in the plate thickness direction. The lower surface 60b is disposed above the first plane 12 of the main body 15. The lower surface 60b is disposed farther away from the lower body 20 in the Z-axis direction than the first plane 12. The first plane is an example of a lower surface at the center of the upper body.

[0037] The lower surface 60b of the shielding plate 60 is disposed higher than the bottom portion 42 of the umbrella portion 40. The lower surface 60b of the shielding plate 60 is disposed higher than the radially inner end portion 42a of the bottom portion 42.

[0038] The shielding plate 60 is fixed to the umbrella portion 40 by, for example, a plurality of screws 62. The shielding plate 60 has through holes formed therein that penetrate in the plate thickness direction. The screws 62 are inserted into the through holes of the shielding plate 60, and heads 62a of the screws 62 are disposed below the lower surface 60b of the shielding plate 60. The umbrella portion 40 has fixing portions 61 to which the screws 62 are fixed. The fixing portion 61 has, for example, a cylindrical shape. A threaded portion is formed on the inner surface of the cylindrical shape. The fixing portion 61 extends downward from, for example, the protruding piece 44. The upper surface 60a of the shielding plate 60 abuts against the lower end of the fixing portion 61. The heads 62a of the screws 62 are disposed above the first flat surface 12 and the tip portion 40a of the umbrella portion 40. In other words, the heads 62a of the screws 62 do not protrude downward below the first flat surface 12 and the tip portion 440a. For example, in a method for manufacturing the ultrasonic anemometer 100, the shielding plate 60 can be fixed to the fixing part 61 by attaching a screw 62 while the shielding plate 60 is pressed against the lower end of the fixing part 61. In addition, the head 62a of the screw 62 may be positioned so as not to protrude from the lower surface 60b of the shielding plate 60.

[0039] 3, the shielding plate 60 is disposed so as to cover the entire opening of the cavity 50 when viewed from below in the Z-axis direction. The shielding plate 60 is not limited to one that covers the entire opening of the cavity 50.

[0040] [Reflection of ultrasonic wave UT2 on the inner surface 43 of the umbrella portion 40] Next, referring to FIG. 9 , the reflection of the ultrasonic wave UT2 on the inner surface 43 of the umbrella portion 40 when the shielding plate 60 is not present will be described. For ease of explanation, ultrasonic waves are shown using straight lines, but ultrasonic waves have directionality and are transmitted so as to spread uniformly from the bottom surface 30b of the ultrasonic transceiver 30. Here, the ultrasonic wave UT1, which is first reflected by the second plane 22, is an ultrasonic wave necessary for measuring the fluid to be measured. On the other hand, the ultrasonic wave UT2, which is first reflected by the third plane 23, is an ultrasonic wave unnecessary for measuring the fluid to be measured. In other words, the ultrasonic wave UT2 is an ultrasonic wave that becomes noise. For example, the ultrasonic wave UT2 (UT2-1) transmitted from the ultrasonic transceiver 31 is reflected by the third plane 23 and travels toward the inner surface 43 of the umbrella portion 40. When the shielding plate 60 is not disposed to cover the cavity 50, the ultrasonic wave UT2-1 is reflected off the inner surface 43 of the umbrella portion 40 and travels toward the second plane 22. The ultrasonic wave UT2 (UT2-2) reflected by the second plane 22 may be received by the ultrasonic transceiver 32.

[0041] In this way, the ultrasonic waves UT2 transmitted from the ultrasonic transceiver 31 may be reflected by the third surface 23 of the lower body 20, the inner surface 43 of the umbrella portion 40, and the second flat surface 22 of the lower body 20, and may be received by the ultrasonic transceiver 32. Such ultrasonic waves UT2 become acoustic noise when measuring the flow velocity and wind direction of air flowing through the flow path 101. If no measures are taken to deal with such acoustic noise, measurement errors will occur in the ultrasonic anemometer 100.

[0042] [Reflection of ultrasonic wave UT3 at shielding plate 60] Next, with reference to FIG. 2 , the reflection of ultrasonic waves UT3 by the shielding plate 60 will be described. For example, ultrasonic waves UT3 transmitted from the ultrasonic transceiver 31 are reflected by the third surface 23 and travel toward the shielding plate 60. When the shielding plate 60 is disposed so as to cover the cavity 50, the ultrasonic waves UT3 are reflected by the lower surface 60b of the shielding plate 60 and travel diagonally downward toward the outside of the third surface 23. In this case, the ultrasonic waves UT3 are not received by the ultrasonic transceiver 32 and do not become acoustic noise. However, particularly when the third surface 23 is inclined outward, ultrasonic waves reflected by the third surface 23 are likely to enter the cavity 50 and be reflected by the inner surface 43. Therefore, providing the shielding plate 60 to reduce the ultrasonic waves entering the cavity 50 can reduce measurement errors. Note that even when the third surface 23 is not formed and the entire upper surface of the reflecting plate 21 is the second flat surface 22, ultrasonic waves may still be incident on the inner surface 43 that forms the cavity 50. Even in such a case, the provision of the shielding plate 60 can reduce measurement errors.

[0043] [Operation and effect of the ultrasonic anemometer 100 according to the first embodiment] The ultrasonic anemometer 100 according to the first embodiment comprises an upper body 10 on which an ultrasonic transmitter / receiver 30 is mounted and in which a hollow portion 50 is formed at a position other than where the ultrasonic transmitter / receiver 30 is located, a lower body 20 arranged at a predetermined distance in the Z-axis direction (first direction) from the upper body 10, and a shielding plate (shielding portion) 60 that covers the opening of the hollow portion 50.

[0044] In such an ultrasonic anemometer 100, the provision of the shielding plate 60 allows ultrasonic waves transmitted from the ultrasonic transmitter / receiver 30 and reflected by the lower body 20 to hit the shielding plate 60. This prevents the ultrasonic waves from traveling into the cavity 50. This prevents the ultrasonic waves from being reflected by the inner surface 43 that forms the cavity 50, preventing unnecessary ultrasonic waves from being received by the ultrasonic transmitter / receiver 30. That is, in the ultrasonic anemometer 100, the shielding plate 60 provides a measure against acoustic noise. As a result, the ultrasonic anemometer 100 achieves improved measurement accuracy.

[0045] In such an ultrasonic anemometer 100, the provision of the shielding plate 60 increased the maximum amplitude of the received signal by approximately 10%. Specifically, the ultrasonic anemometer according to the comparative example, which did not have the shielding plate 60, had an attenuation rate of 12.1%, while the ultrasonic anemometer 100 equipped with the shielding plate 60 had an attenuation rate of 2.4%. The attenuation rate can be expressed by the following formula (1). For example, the attenuation rate of the received signal received 450 μs after the start of transmission of the transmitted signal can be calculated using the following formula (1). Attenuation rate = (maximum received amplitude - received amplitude) / maximum amplitude (1)

[0046] In the ultrasonic anemometer 100, the hollow portion 50 is positioned outside the ultrasonic transmitter / receiver 30 in the X-axis direction (second direction), and a third surface 23 is formed on the outer periphery of the lower body 20, which is an inclined portion that slopes away from the upper body 10 in the Z-axis direction as it moves outward in the X-axis direction.

[0047] In the ultrasonic anemometer 100 configured as described above, the third surface 23 is formed on the outer periphery of the lower body 20, allowing ultrasonic waves reflected by the third surface 23 to travel outside. In the ultrasonic anemometer 100, ultrasonic waves that would become acoustic noise can be traveled outside so that they are not received by the receiving ultrasonic transceiver 30. On the other hand, if the shielding plate 60 is not provided, the ultrasonic waves UT2-2 reflected by the third surface 23 become noise and interfere with the ultrasonic waves UT1 necessary for wind speed measurement, canceling out the ultrasonic waves UT1.

[0048] In the ultrasonic anemometer 100, a plurality of ultrasonic transmitters / receivers 30 are mounted on the upper body 10 and spaced apart in the X-axis direction (second direction). The upper surface of the lower body 20 includes a second plane 22 that intersects with the Z-axis direction, and a third surface 23 of the lower body 20 is disposed outside the second plane 22 in the X-axis direction, and a portion of the third surface 23 of the lower body 20 is disposed directly below the ultrasonic transmitters / receivers 30.

[0049] The ultrasonic waves transmitted from the ultrasonic transmitter / receiver 31 reach the ultrasonic transmitter / receiver 32 while reflecting between the lower body 20 and the upper body 10. The distance between the lower body 20 and the upper body 10 determines the transmission distance of the ultrasonic waves. By adjusting this transmission distance, the ultrasonic waves transmitted from the ultrasonic transmitter / receiver 31 can reach the ultrasonic transmitter / receiver 32 at their strongest. To adjust this transmission distance, it is preferable to reduce the number of times the ultrasonic waves reflect between the lower body 20 and the upper body 10. The number of reflections is preferably three or less. With the ultrasonic anemometer 100 configured as described above, a portion of the ultrasonic waves transmitted from the ultrasonic transmitter / receiver 30 is reflected by the third surface 23 located directly below the ultrasonic transmitter / receiver 30 and travels outside the ultrasonic anemometer 100. This limits the number of times the ultrasonic waves transmitted from the ultrasonic transmitter / receiver 30 reflect between the lower body 20 and the upper body 10. In the ultrasonic anemometer 100, the ultrasonic waves received by the ultrasonic transmitter / receiver 32 can be optimized.

[0050] In the ultrasonic anemometer 100, the upper body 10 includes a main body 15 on which the ultrasonic transceiver 30 is mounted, and an inclined portion 45 arranged outside the main body 15 in the X-axis direction. A hollow portion 50 is formed between the inclined portion 45 of the upper body 10 and the main body 15 in the X-axis direction. The inner surface 43 of the inclined portion 45 of the upper body 10 includes an inclined surface whose upper end is arranged more inward than the lower end. The lower end of the inner surface 43 is arranged more outward in the radial direction of the main body 15 than the upper end of the inner surface 43.

[0051] In the ultrasonic anemometer 100, the umbrella portion 40 including the inclined portion 45 is provided on the upper body 10, thereby preventing raindrops 110 from entering the flow path 101. Furthermore, adhesion of the raindrops 110 to the bottom surface 30b of the ultrasonic transceiver 30 is prevented. As a result, the ultrasonic anemometer 100 reduces the influence of the raindrops 110 on the measurement results obtained by the ultrasonic transceiver 30. In the ultrasonic anemometer 100, the influence of the raindrops 110 is reduced during rainy weather, improving the measurement accuracy of wind speed and wind direction. Furthermore, in the ultrasonic anemometer 100, the structure having the umbrella portion 40 includes a shielding plate 60 disposed to cover the cavity 50 from below, thereby preventing ultrasonic waves from traveling into the cavity 50 and reducing ultrasonic waves impinging on the inner surface 43.

[0052] Furthermore, if the width of the bottom of the umbrella portion 40 (the width along the X-axis direction from the straight line L15 to the tip 40a of the inclined portion 45) is greater than the thickness t15 of the portion constituting the bottom of the main body 15, it is preferable to manufacture the umbrella portion 40 by injection molding rather than casting in order to improve the processing accuracy of the umbrella portion 40. In the case of injection molding, the thickness of each portion of the upper body 10 needs to be approximately the same, so a hollow portion 50 is formed. Here, if the upper body 10 is manufactured by injection molding, the thickness of the inclined portion 41 of the upper body 10 will be thinner than the width of the lowest part of the hollow portion 50. In other words, the thickness of the inclined portion 41 of the upper body 10 will be thinner than the width W60 of the shielding plate 60 in the X-axis direction.

[0053] However, in the ultrasonic anemometer 100, the shielding plate 60 prevents ultrasonic waves from traveling into the cavity 50, thereby providing a measure against acoustic noise. According to this embodiment, it is possible to provide an ultrasonic anemometer 100 that has been provided with a measure against acoustic noise.

[0054] In the ultrasonic anemometer 100, the inner surface 43 of the inclined portion 45 of the upper body 10 is disposed outward in the X-axis direction from the third surface 23 of the lower body 20. The "outward" side is the side farther from the center line CL1 of the upper body 10 in the radial direction of the main body 15.

[0055] With the ultrasonic anemometer 100 configured as described above, the inclined portion 45 extends outward in the X-axis direction beyond the third surface 23 of the lower body 20, thereby preventing raindrops 110 from entering the flow path 101. With this ultrasonic anemometer 100, it is possible to prevent raindrops 110 from adhering to the first flat surface 12, the second flat surface 22, and the bottom surface 30b of the ultrasonic transceiver 30, and to prevent a decrease in the accuracy of measuring wind speed and wind direction.

[0056] In the ultrasonic anemometer 100, the lower surface 60b of the shielding plate 60 is disposed farther away from the lower body 20 in the Z-axis direction than the first plane (the lower surface at the center) 12 of the upper body 10. In other words, the lower surface 60b of the shielding plate 60 is disposed above the first plane 12. The lower surface 60b of the shielding plate 60 is not disposed below the first plane 12.

[0057] With the ultrasonic anemometer 100 configured as described above, the shielding plate 60 can be placed in a position that does not interfere with the flow of air flowing between the first plane 12 and the second plane 22. As a result, the generation of turbulence by the shielding plate 60 is prevented, and the wind speed can be measured with high accuracy.

[0058] In the ultrasonic anemometer 100, the shielding plate 60 is fixed to the upper body 10 by a screw (fixing member) 62, and the head (lower surface) 62a of the screw 62 is located above the lower surface of the upper body 10. The fixing member is not limited to the screw 62, and may be any other rod-shaped fixing member. The lower surface of the upper body 10 may be the first plane 12 or the tip portion 40a of the inclined portion 45.

[0059] In the ultrasonic anemometer 100 configured as described above, the heads 62a of the screws 62 can be positioned so as not to interfere with the flow of air flowing between the first plane 12 and the second plane 22. As a result, turbulence caused by the screws 62 can be prevented, enabling accurate measurement of wind speed. In addition, the ultrasonic anemometer 100 allows the shielding plate 60 to be fixed to the upper body 10 by tightening the screws 62 from below.

[0060] In the ultrasonic anemometer 100, the inclined portion 45 of the upper body 10 is plate-shaped and is formed to surround the main body 15. The upper body 10 has an umbrella portion 40 including the inclined portion 45. The plate thickness direction of the inclined portion 45 of the umbrella portion 40 is inclined with respect to the Z-axis direction, and the bottom portion (lower surface) 42 of the inclined portion 45 of the umbrella portion 40 includes an inclined surface inclined with respect to the XY plane (horizontal plane). The inner end portion 42a of the bottom portion 42 of the inclined portion 45 of the umbrella portion 40 is positioned higher than the outer tip portion 40a of the bottom portion 42. The lower surface 60b of the shielding plate 60 is positioned higher than the bottom portion 42 of the inclined portion 45 of the umbrella portion 40.

[0061] In the ultrasonic anemometer 100 configured as described above, the bottom 42 of the umbrella portion 40 is configured as an inclined surface that can function as a draining surface. By positioning the inner end 42a of the inclined surface of the bottom 42 at a position higher than the outer tip 40a, raindrops that move downward along the outer inclined surface 41 of the umbrella portion 40 are prevented from moving along the bottom 42 into the inside of the umbrella portion 40. In the ultrasonic anemometer 100, the underside 60b of the shielding plate 60 is positioned higher than the inner end 42a of the bottom 42 of the umbrella portion 40, thereby preventing raindrops from entering and positioning the shielding plate 60 in a position that does not interfere with the flow of air flowing into the flow path 101, thereby reducing acoustic noise.

[0062] In the ultrasonic anemometer 100, the shielding plate 60 is plate-shaped, and the thickness direction of the shielding plate 60 is along the Z-axis direction. In other words, the lower surface 60b of the shielding plate 60 is disposed so as to be along the XY plane.

[0063] In the ultrasonic anemometer 100 having this configuration, the first plane 12, the second plane 22, and the lower surface 60b of the shielding plate 60 are arranged parallel to each other, thereby positioning the shielding plate 60 so as not to interfere with the flow of air between the first plane 12 and the second plane 22, thereby reducing acoustic noise. Furthermore, if the shielding plate 60 is not parallel to the first plane 12 and the second plane 22, ultrasonic waves reflected by the shielding plate 60 may travel inside the ultrasonic anemometer 100. As a result, the acoustic noise reduction effect may be reduced. Therefore, it is preferable to arrange the first plane 12, the second plane 22, and the lower surface 60b of the shielding plate 60 parallel to each other. Furthermore, to prevent ultrasonic waves from entering the cavity 50, it is preferable to position the shielding plate 60 near the bottom of the cavity 50. It is preferable that the lower surface 60b of the shielding plate 60 be substantially flush with the bottom 42 of the inclined portion 45 of the umbrella portion 40.

[0064] [Ultrasonic anemometer 100B according to Modification 1] Next, an ultrasonic anemometer 100B according to Modification 1 will be described with reference to Fig. 5. Fig. 5 is a schematic cross-sectional view illustrating the ultrasonic anemometer 100B according to Modification 1. The ultrasonic anemometer 100B according to Modification 1 shown in Fig. 5 differs from the ultrasonic anemometer 100 shown in Fig. 4 in that it includes a shielding plate 60B instead of the shielding plate 60. The shielding plate 60 is formed so as to cover the entire opening of the cavity 50, but the shielding plate 60B does not cover the entire opening of the cavity 50. Note that in the description of Modification 1, descriptions that are the same as those in the first embodiment may be omitted.

[0065] The shielding plate 60B is formed in an annular shape when viewed in the plate thickness direction. A gap is formed between the shielding plate 60B and the side surface 15a of the main body 15 in the X-axis direction. The shielding plate 60B and the inner surface 43 of the inclined portion 45 are in contact with each other in the X-axis direction. The gap between the shielding plate 60B and the main body 15 is continuous around the entire circumference of the main body 15. In the circumferential direction of the main body 15, the shielding plate 60B and the side surface 15a of the main body 15 may be in partial contact with each other.

[0066] The ultrasonic anemometer 100B according to the first modification has the same effects as the ultrasonic anemometer 100. The shielding plate 60B does not have to cover the entire opening of the cavity .

[0067] [Ultrasonic anemometer 100C according to Modification 2] Next, an ultrasonic anemometer 100C according to Modification 2 will be described with reference to FIG. 6. FIG. 6 is a schematic cross-sectional view illustrating the ultrasonic anemometer 100C according to Modification 2. The ultrasonic anemometer 100C according to Modification 2 shown in FIG. 6 differs from the ultrasonic anemometer 100 shown in FIG. 4 in that it includes a shielding plate 60C instead of the shielding plate 60. The shielding plate 60C covers most of the opening of the cavity 50, but does not cover the entire opening. Note that in the description of Modification 2, descriptions that are the same as those in the first embodiment and Modification 1 may be omitted.

[0068] The shielding plate 60C is formed in an annular shape when viewed in the plate thickness direction. A gap is formed between the shielding plate 60C and the inner surface 43 of the inclined portion 45 in the X-axis direction. The shielding plate 60C and the side surface 15a of the main body 15 are in contact in the X-axis direction. The gap between the shielding plate 60C and the inner surface 43 of the inclined portion 45 is continuous around the entire circumference of the umbrella portion 40. The shielding plate 60C and the inner surface 43 of the inclined portion 45 may be in partial contact in the circumferential direction of the umbrella portion 40.

[0069] The ultrasonic anemometer 100C according to the second modification has the same effects as the ultrasonic anemometer 100. The shielding plate 60C does not have to cover the entire opening of the cavity .

[0070] [Ultrasonic anemometer 100D according to Modification 3] Next, an ultrasonic anemometer 100D according to Modification 3 will be described with reference to FIG. 7. FIG. 7 is a schematic cross-sectional view illustrating the ultrasonic anemometer 100D according to Modification 3. The ultrasonic anemometer 100D according to Modification 3 shown in FIG. 7 differs from the ultrasonic anemometer 100 shown in FIG. 4 in that it includes a shielding plate 60D instead of the shielding plate 60. The shielding plate 60D covers most of the opening of the cavity 50, but does not cover the entire opening. Note that in the description of Modification 3, descriptions that are the same as those in the first embodiment, Modification 1, and Modification 2 may be omitted.

[0071] The shielding plate 60D is formed in an annular shape when viewed in the plate thickness direction. A through hole is formed in the shielding plate 60D, penetrating in the plate thickness direction. This through hole may be formed in the center in the width direction of the shielding plate 60D. The width direction of the shielding plate 60D may be the X-axis direction in FIG. 7. The through hole is formed partially in the circumferential direction of the shielding plate 60D. The shielding plate 60D may be in contact with the side surface of the main body 15. The shielding plate 60D may be in contact with the inner surface 43 of the inclined portion 45.

[0072] The ultrasonic anemometer 100D according to the third modification also has the same effects as the ultrasonic anemometer 100. The shielding plate 60D does not have to cover the entire opening of the cavity .

[0073] [Ultrasonic anemometer 100E according to Modification 4] Next, an ultrasonic anemometer 100E according to Modification 4 will be described with reference to Fig. 8. Fig. 8 is a schematic cross-sectional view illustrating the ultrasonic anemometer 100E according to Modification 4. The ultrasonic anemometer 100E according to Modification 4 shown in Fig. 8 differs from the ultrasonic anemometer 100 shown in Fig. 8 in that a shielding portion 60E is arranged so as to fill the hollow portion 50. Note that in the description of Modification 4, descriptions that are the same as those in the first embodiment and Modifications 1 to 3 may be omitted.

[0074] The shielding portion 60E may be made of, for example, resin. The shielding plate 60E is formed in a circular ring shape when viewed in the Z-axis direction. For example, the shielding plate 60E may be formed by filling the cavity 50 with resin or the like.

[0075] The ultrasonic anemometer 100E according to the fourth modification also provides the same effects as the ultrasonic anemometer 100. The shielding portion that covers the opening of the cavity 50 is not limited to being plate-shaped.

[0076] It should be noted that the present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form.

[0077] In the above embodiment, the ultrasonic anemometer 100 is exemplified in which the shielding plate 60 is formed to shield the opening of the cavity 50 in the umbrella part 40, but the cavity is not limited to being formed in the umbrella part 40. For example, in the ultrasonic anemometer 100, a shielding part may be formed to shield the opening of the cavity formed in the main body 15. [Explanation of symbols]

[0078] 100, 100B, 100C, 100D, 100E: ultrasonic anemometer, 10: upper body, 11: top plate, 12: first plane (underside of center of upper body), 15: main body, 20: lower body, 21: reflector, 22: second plane, 23: third plane (inclined portion of lower body), 30: ultrasonic transmitter / receiver, 31: ultrasonic transmitter / receiver, 32: ultrasonic transmitter / receiver, 40: umbrella portion, 40a: tip portion (outer end of underside of inclined portion), 42: bottom portion (underside of inclined portion), 42a: end portion (inner end of underside of inclined portion), 43: inner surface (inclined surface), 45: inclined portion (inclined portion of upper body), 50: hollow portion, 60, 60B, 60C, 60D: shielding plate (shielding portion), 60a: upper surface (upper surface of shielding portion), 60b: lower surface (lower surface of shielding portion), 62: screw (fixing member), 62a: head, CL1: center line (center of upper body), X: X-axis direction (second direction), Y: Y-axis direction (third direction), Z: Z-axis direction (first direction), θ2: inclination angle (inclined angle of inclined portion of upper body), θ3: inclination angle (inclined angle of inclined portion of lower body).

Claims

1. an upper body on which an ultrasonic transmitter / receiver is mounted and in which a cavity is formed at a position other than the portion where the ultrasonic transmitter / receiver is disposed; a lower body disposed at a predetermined distance in a first direction from the upper body; a shielding portion that covers the opening of the cavity portion.

2. the cavity is disposed outside the ultrasonic transmitter / receiver in a second direction intersecting the first direction, 2. The ultrasonic anemometer according to claim 1, wherein an inclined portion is formed on the outer periphery of the lower body such that the outer periphery is inclined away from the upper body in the first direction.

3. The upper body is provided with a plurality of the ultrasonic transmitters / receivers that are spaced apart in a second direction that intersects with the first direction, an upper surface of the lower body includes a plane intersecting with the first direction; The inclined portion of the lower body is disposed outside the plane in the second direction, 3. The ultrasonic anemometer according to claim 2, wherein a part of the inclined portion of the lower body is disposed directly below the ultrasonic transmitter / receiver.

4. The upper body is a main body on which the ultrasonic transmitter / receiver is mounted; an inclined portion disposed on an outer side of the main body in a second direction intersecting the first direction; the cavity is formed between the inclined portion of the upper body and the main body in the second direction, The ultrasonic anemometer according to claim 1 , wherein the inner surface of the inclined portion of the upper body includes an inclined surface whose upper end is located more inward than its lower end.

5. The ultrasonic anemometer according to claim 4 , wherein the inclined portion of the upper body is disposed further outward than the inclined portion of the lower body in the second direction.

6. an upper surface of the lower body includes a plane intersecting with the first direction; 2. The ultrasonic anemometer according to claim 1, wherein the lower surface of the shielding portion is parallel to the plane.

7. 2. The ultrasonic anemometer according to claim 1, wherein a lower surface of the shielding portion is disposed farther from the lower body in the first direction than a lower surface of a central portion of the upper body.

8. the shielding portion is fixed to the upper body by a fixing member, The ultrasonic anemometer according to claim 7 , wherein a lower surface of the fixing member is disposed higher than a lower surface of the upper body in the first direction.

9. The inclined portion of the upper body has a plate shape and is formed to surround the main body, a thickness direction of the inclined portion of the upper body inclined with respect to the first direction, a lower surface of the inclined portion of the upper body includes an inclined surface inclined with respect to a horizontal plane, an inner end of a lower surface of the inclined portion of the upper body is disposed higher than an outer end of the lower surface, 5. The ultrasonic anemometer according to claim 4, wherein a lower surface of the shielding portion is disposed higher than a lower surface of the inclined portion of the upper body.

10. 2. The ultrasonic anemometer according to claim 1, wherein the thickness of the inclined portion of the upper body is thinner than the width of the shielding portion in a second direction intersecting the first direction.

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